The CX and CF standard sliding sleeves are downhole valves that can be installed in the production string to provide communication between the tubing/casing annulus. These sleeves are economical with many versatile options. The sleeves are opened and closed using standard wireline methods. An inner sleeve designated as ‘D’ is shifted downward to open the tool and upward to close it. An inner sleeve designated as ‘U’ is shifted upward to open the tool and downward to close it. Sleeves are designed with a nipple profile on the upper sub to accommodate flow-control locks with either a Otis ‘X’ or Baker ‘F’ profile. All of the sleeves are designed such that the circulation/flow area is at least equal to the tubing size it is designed for. The standard sleeves incorporate the proven ‘vee’ seal design and can be varied to suit the environment and/or the application it is to be used in. The sleeves are designed so that normal wireline, coil or other operations will not open or close the sleeves inadvertently. Equalizing ports in the inner sleeve allows for equalizing when shifting the sleeve open in high pressure differential applications.